Airspace over East Ukraine has been shut down following the crash of a Malaysia Airlines Boeing 777.

Airlines including Deutsche Lufthansa and KLM have said they will avoid flying over eastern Ukraine after the crash of a Malaysian Airlines jet. Delta Air Lines is staying away from the whole country.

"Lufthansa has decided to avoid the east Ukrainian air space by a wide margin with immediate effect," a company spokeswoman said. The airline would continue to serve the airports of Kiev and Odessa for now, she added.

Air New Zealand does not operate any services over Eastern Europe. Turkish Airlines, Russia's Aeroflot and Russian airline Transaero said their planes would steer clear of the territory.

US carriers have voluntarily agreed not operate in the airspace near the Russian-Ukraine border, the Federal Aviation Administration said in an email. Italy's aviation agency ENAC said its airlines should avoid flying over the area as well.

Carriers from the United States to Europe are having to reassess their routes over the region after a Boeing 777 passenger jet was downed in an area that has been the main battleground involving Russian control over parts of Ukraine.

Air traffic control and airlines should have been more cautious of the area, said Brent Spencer of Embry-Riddle Aeronautical University.

"The fact that the airspace is not restricted doesn't mean you don't need to give extra consideration whether you want to fly to it or not," said Spencer, who is director of Embry- Riddle's air-traffic control program in Prescott, Arizona.

"You might want to think twice about flying through an airspace where there's somebody shooting missiles at anybody."

The area was a popular route for flights going between Europe and Asian cities such as Singapore, Mikael Robertsson, co-founder of Stockholm-based Flightradar24, said in an interview.

The Malaysia Air flight was en route to Kuala Lumpur from Amsterdam when it went down near the eastern town of Torez, killing almost 300 people on board.

The airspace over the region was closed to air traffic up to 32,000 feet, according to Eurocontrol, an international organisation which coordinates European air traffic agencies. The Malaysia Air flight was flying 1,000 feet above the restricted space.

The Ukrainian government in Kiev has said the plane was shot down by pro-Russian rebels. The separatists denied the accusation.

Delta, the third-largest US carrier, is going to avoid all Ukrainian airspace "out of an abundance of caution," according to a statement on the Atlanta-based company's website.

The region wasn't subject to any alerts to pilots, known as notices to airmen, said Perry Flint, a spokesman for the International Air Transport Association in Washington.

The FAA had barred U.S. airlines from flying over southern areas of Ukraine in a notice issued April 3, after Russia annexed the region of Crimea. That notice didn't cover the area where the Malaysian plane crashed.

The FAA had issued the restriction because Russia had attempted to assert control over flights above Crimea, which the U.S. considered "unilateral and illegal," according to an e- mail today from the agency. Flights by U.S. carriers were steered away because of the potential for conflicting instructions by controllers from Russia and Ukraine, according to the statement.

Prior to the turmoil in the Ukraine, there were about 300 to 400 flights a day that flew over the region, Robertsson said. In recent months, there have been about 100 a day, he said.

Within a short time of the crash, the flight routes were emptied of international flights, he said.

Lufthansa, which has its main hub in Frankfurt, is diverting flights, according to a spokesman, Thomas Janchow. KLM, whose booking codes were shared on Malaysian Air Flight 17, said "as a precautionary measure KLM avoids flying over the concerned territory," according to the Dutch carrier.

"Although not yet officially confirmed by Malaysia Airlines, it is with great regret that KLM has learnt about the possible incident with flight MH17, codeshare KL4103," the airline said. The carrier is a unit of Air France-KLM Group.

The European Cockpit Association, a pilot group, said by email that the Malaysian plane's path was "the most common route for flights from Europe to South East Asia." British Airways said its flights don't traverse eastern Ukraine, though the company is putting its daily London-Kiev route under review.

Josh Freed, a spokesman for American Airlines Group, said the world's largest carrier was checking on whether any of its planes fly in the area. United Continental Holdings Inc., the second-biggest airline, doesn't fly through Ukrainian airspace.

Airlines have been paring service to Ukraine, with Lufthansa halting flights to Donetsk as tension escalated between the government and separatist rebels.

Emirates, the biggest carrier by international traffic, said this month that it would suspend its flight linking Dubai and Kiev from August 1, citing political uncertainty.